Portion of a shower tray



FIG. 1 is a top perspective view of a portion of a shower tray showing my new design;

FIG. 2 is a bottom perspective view thereof;

FIG. 3 is a top view thereof; and,

FIG. 4 is a bottom view thereof.

The broken lines showing the remainder of the portion of a shower tray are for environmental purposes only and form no part of the claimed design. 

CLAIM The ornamental design for a portion of a shower tray, as shown and described. 